20% Vinegar

Nothing kills weeds faster than 20% Horticultural Vinegar. This non-selective acid burns weeds back to the roots. Use full strength on all types of weeds. You can increase its effectiveness by adding a small amount of natural Orange Oil to each gallon of 20% Vinegar. Orange oil is also commonly used as an organic herbicide. Together they make a potent weed killer. Adding one or two drops of any dishwashing liquid is also recommended to serve as a surfactant, which makes your mixture adhere to weeds.
 
Pick any sunny day and spray the crown of each weed thoroughly. In a few hours, you’ll have dead weeds!